An object eight times the mass of Jupiter may have swooped around the sun, coming superclose to Mars' present-day orbit ...

"In January, you'll have the opportunity to take in four bright planets in a sweeping view" said Preston Dyches of NASA's Jet ...

When you first learned about the Solar System, you probably saw diagrams that made it look orderly, with planets arranged in ...

Ever since Isaac Newton famously talked about gravity, its dominance as a force in our solar system has been well known. It's ...

There may be an undiscovered planet in the outer solar system whose presence is revealed by the strange orbit of objects beyond the eighth planet Neptune. The tantalizing prospect of a ninth ...